1. Field of the Invention
This invention relates to an automatic mixture control device for a carburetor. More specifically, it relates to a device that compensates for naturally occurring rich/lean variations associated with changes in elevation, temperature and humidity.
2. Description of the Prior Art
Various devices and apparatus to swirl the air and fuel mixture as it enters the combustion chamber of an internal combustion engine have been proposed and employed for various purposes. Such devices have involved both stationary as well as rotating members at various physical locations in order to solve specific problems. For example, U.S. Pat. Nos. 3,077,391, 3,938,967 and 4,092,966 have suggested the use of stationary blades or vanes between the carburetor and intake manifold with the intent of creating a high degree of turbulence for atomizing and more completely vaporizing the fuel for improved performance. U.S. Pat. No. 3,437,467 additionally suggests the introduction of air within a helical swirl vane structure located between the carburetor and the intake manifold for the same atomizing purpose, while U.S. Pat. No. 3,544,290 employs a strainer followed by a sonic vibrator which could either be a stationary member or a rotating propeller.
Various other patents have suggested other rotating or rotatable members between the carburetor and intake manifold including a sieve followed by a flow driven spinning bowl of U.S. Pat. No. 3,946,717 and a droplet collector followed by a set of rotatable impellers of U.S. Pat. No. 3,955,548. In U.S. Pat. No. 4,080,943 a pair of counterrotating paddles are employed while in U.S. Pat. No. 4,116,187 a paddle wheel type blender and charger apparatus is disclosed and in U.S. Pat. No. 4,153,028 a cylindrical rotator with openings is used.
Other physical locations for such devices have been suggested such as stationary vanes near each intake valve internal to the combustion chamber as in U.S. Pat. No. 1,969,202 and similar vanes on the intake manifold side near the valves as in U.S. Pat. No. 4,151,816. In U.S. Pat. Nos. 2,027,480 and 2,051,556 a rotating device at the base of the intake manifold is disclosed to distribute liquid droplets particularly during periods of acceleration. In fact, rotatable membes have been employed as essentially the exclusive means for vaporizing fuel such as in some very early rotating fan carburetors of U.S. Pat. Nos. 1,106,452 and 1,150,115 and later in U.S. Pat. No. 2,665,892.
More recently, for example in U.S. Pat. No. 4,130,099, a gas saving device between the carburetor and intake manifold involving a spiral grooved venturi to provide spin within the manifold is employed and in U.S. Pat. No. 3,395,899 a fuel injection system with a cyclonic flow inducing member is combined with a conventional booster venturi system to reduce emissions and improve operating characteristics.
However, essentially all of the above devices ignore a fundamental problem associated with the contemporary gasoline carburetor employing a booster venturi system. Thus, none of the above references alleviate the inherent fuel to air mixture enriching which occurs with increased elevation and fuel to air mixture leaning associated with a decrease in the ambient temperature and similar effects associated with humidity variations. Consequently, it is still a common practice to retune and adjust the carburetor when traveling in mountainous areas or during seasonal changes.